Aplodinotus grunniens

Adaptation

The drum ascertains itself in its environment by
using otoliths, earbones found in the inner ear, that
are sensitive to gravity and linear acceleration.
Otoliths are made up of a combination of a gelatinous
matrix and calcium carbonate. The age of the drum can be
calculated according to this structure as it grows with
the drum. To read more about the uses of this unique structure
by humans follow the link~
Facts. The drum also orients itself by the lateral
line, a sense organ used to detect motion in the water.
It is the only freshwater fish in which the lateral line
runs straight down the body all the way into the tail.

The Freshwater Drum is unique in that every member of
its family Sciaenidae has an elaborate swimbladder which
acts as a resonating chamber, amplifying the noises
produced by the adjacent muscles. This sound production
is voluntary and mostly created by males. Drumming
generally occurs after sunset and during spawning season
when the male "drums" to attract his mate. Read
Reproduction to learn more.

The drum has adapted to its environment with the development of
modified pharyngeal teeth which crush the shells of mollusks, its
main food source. To learn more check out
Interactions